Try deleting the instance if creation fails

If we fail to create an instance, try deleting the instance first and then try
to create it again. That will clean up any running instance.

Also, add some instructions to the README.md to explain how to bootstrap the
Google Cloud SDK.
Build docker images

This patch teaches the system how to build docker images and how to run as
someone other than jamesr.
Merge pull request #7 from domokit/delete_instance

Try deleting the instance if creation fails